The spirit collection includes specimens preserved in liquid (not just alcohol), mainly of Algae and Vascular Plants, as well as some Fungi. It is interesting both from a scientific and historical viewpoint.
This collection contains various species. There are very few Lichens and Bryophytes because they can be easily restored from the dry condition in the herbaria. The Algae are fixed in the field using formalin, which also acts as a preservative. All the other groups are generally fixed for 48 h in a mixture of alcohol, formalin and acetic acid, then transferred to a preservative mixture (alcohol, water and glycerine). These treatments provide material more favourable to analysis than straight from the Herbarium.
While the oldest preserved specimen seems to be an Acetabularia (Algae, Dasycladaceae) prepared on blue glass in 1845, ahead of an exhibition, the current spirit collection is organised around two core collections gathered together mainly between 1950 and 1975: Roger HEIM’s Mushrooms (various origins, a wide range of nomenclatural types, including the famous Mexican hallucinogenic mushrooms) and René CAPURON’s Collection of Forest Angiosperms from Madagascar (a fundamental part of Madagascar’s Flora).
The specimens are mainly of tropical origin, particularly French Guiana, the Antilles, West Africa, etc. Some of the collection series are specialised, like the New Caledonian Gymnosperms and the Malagasy Kalanchoe, cultivated in the greenhouses of St Jean–Cap–Ferrat and fixed in the early 1950s. On the other hand, the "Algae" section contains some mixed collections, with samples collected on dragging trips (Calypso expedition in 1956, Algae from the Azores collected by F. ARDRÉ, etc.). Likewise, the Orchids can be grouped together by lots.
The wide variety of containers tells a story in itself: the cylindrical blown glass jars of the 19th century gave way to jars with steel strips, then "Parfait" red rubber jars. Often the makeshift containers used in the field (bottles, baby food pots, gherkin jars, pill boxes, even film containers) have been kept as they are, which is not ideal for storage (non-standard sizes, difficulties with labelling) nor preservation (not airtight). Large items (such as Palms) are placed in drums (plastic kegs). Some technical problems must be solved on a case-by-case basis: type of labelling (in and on the jar, on sturdy materials, in pencil or waterproof ink), location of bar codes and more recently, replacement of formalin by less carcinogenic substances.
For the specimens in this collection, the natural volumes are less modified, the colours have not altered so much, and the lightening effect of the mixtures clearly highlights the veins in the leaves and floral parts. Lastly, an in-depth anatomical study can be undertaken, as the living content of the cells is also fixed, apart from inclusions such as starch grains, crystals and resins. The Alcoothèque’s role is therefore to provide raw materials for dissection, enabling an accurate – i.e. similar to the living state – illustration of the structures.